Selective cleavage of Arg!Thr and Arg!Ile in prothrombin to form thrombin and two inactive fragments

Comment

From the venom of the Taipan snake (Oxyuranus scutellatus). Converts prothrombin to thrombin. Specificity is similar to that of Factor Xa (EC 3.4.21.6). However, unlike Factor Xa this enzyme can cleave its target in the absence of coagulation Factor Va. Activity is potentiated by phospholipid and Ca2+ which binds via gamma-carboxyglutamic acid residues. Similar enzymes are known from the venom of other Australian elapid snakes, including Pseudonaja textilis textilis, Oxyuranus microlepidotus and Demansia nuchalis affinis.